Integrated circuit devices, edge seals therefor

ABSTRACT

An edge seal for a chip with integrated circuits. A first metal line extends along a periphery of the chip, with a first inter-metal dielectric layer on the first metal line. A second metal line overlies the first inter-metal dielectric layer and extends along the periphery of the chip. A plurality of first metal plugs in the first inter-metal dielectric layer connects the first metal line and the second metal line and at least one first metal wall in the first inter-metal dielectric layer is laterally adjacent to a periphery of the first metal line.

BACKGROUND

The present invention relates to integrated circuits, more particularly,to edge seals for chips.

Edge seals for chips are generally used as mechanical and electricalbarriers to contamination introduced in the chip sawing process.

FIG. 1 shows a semiconductor wafer 300 with a plurality of semiconductorchips 200 arranged in an array. Each semiconductor chip 200 containscircuitry to perform a specific function and has an edge seal 100disposed along the edge thereof to prevent contamination by moisture andmetal particles. Scribe lines 302 are arranged between semiconductorchips 200 where a saw can pass when separating the semiconductor chip.

FIG. 2 is a top view of semiconductor chip 200 comprising the edge seal100 and FIG. 3 is a cross sectional view taken along line A–A′ ofshowing a dielectric layer IL on a semiconductor wafer 1 with aplurality of tungsten plugs 2 and metal lines 3, 5, 7, 9 of copper inthe dielectric layer IL. Metal lines 3, 5, 7, and 9 are approximatelyparallel. A plurality of metal walls 4 are disposed between metal lines3 and 5 comprising a plurality of trenches filled with a copper layer.

A plurality of metal walls 6 are disposed between the metal lines 5 and7 with a plurality of metal walls 8 between metal lines 7 and 9. Metalwalls 4, 6 on adjacent metal lines are staggered in the dielectric layerIL. Metal walls 6, 8 on the adjacent metal lines are also staggered anddisposed in the dielectric layer IL.

Distance d1 between the metal wall 4 and the edges of metal lines 3 or 5is large enough that delimitation P may occur at the dielectric layer ILat the edges of the metal lines 3 or 5 by thermal stress duringpackaging or test process.

SUMMARY

In view of the above disadvantages, edge seals for chips to protectintegrated circuits and integrated circuit devices using the edge sealsare provided. Embodiments of such edge seals comprise a first metalline, a first inter-metal dielectric layer, a second metal line, aplurality of first metal plugs and at least one first metal wall. Thefirst metal line extends along a periphery of the chip. The firstinter-metal dielectric layer is on the first metal line. The secondmetal line overlies the first inter-metal dielectric layer and extendsalong the periphery of the chip. The first metal plugs in the firstinter-metal dielectric layer connect the first and second metal line.The first metal wall in the first inter-metal dielectric layer islaterally adjacent to a periphery of the first metal line, in which thefirst metal wall is connected to the first metal line and the secondmetal line.

The first metal wall is separated by less than one micron from theperiphery of the first metal line.

Alternately, an embodiment of an edge seal may comprise a plurality ofinter-metal dielectric layers, a plurality of metal lines, a pluralityof metal plugs in the inter-metal dielectric layers and a plurality ofmetal walls formed in the inter-metal dielectric layers, with each ofthe metal walls adjacent to a periphery of the metal plugs andconnecting adjacent metal lines. Also, each metal line on theinter-metal dielectric layers extends along a periphery of the chip.Each of the metal plugs in the same inter-metal dielectric layerconnects adjacent metal lines. Each of the metal walls in the sameinter-metal dielectric layer adjacent to a periphery of the metal linespreferably connects adjacent metal lines. The metal plugs are preferablyarranged in an array in each of the inter-metal dielectric layers withthe metal plugs in each of the inter-metal dielectric layers preferablyaligned with those in adjacent inter-metal dielectric layers.Alternately, the metal walls formed in the adjacent inter-metaldielectric layers are substantially aligned with each other.

Also, provided are embodiments of integrated circuit devices utilizingthe edge seals.

DESCRIPTION OF THE DRAWINGS

The disclosure can be more fully understood with reference to thefollowing drawings.

FIG.1 is a top view of a semiconductor wafer with an edge seal along theedges of the chips.

FIG. 2 is a top view of a semiconductor chip having a conventional edgeseal.

FIG. 3 is a cross sectional view along line A–A′ of FIG. 2.

FIG. 4 is a top view of an embodiment of a semiconductor chip with anedge seal thereon.

FIG. 5 a is a cross sectional view taken along line B–B′ of FIG. 4.

FIG. 5 b is top view of inter-layer metal plugs and inter-layer metalwalls of the edge seal in FIG. 5 a.

FIG. 5 c is top view of another arrangement of inter-layer metal plugsand an inter-layer metal wall.

FIG. 5 d is an enlarged sectional perspective view of FIG. 5 a.

FIG. 5 e is a top view of a metal line extending along the periphery ofa chip.

FIG. 6 is a top view of another embodiment of a semiconductor chip withedge seal thereon.

FIG. 7 is a cross sectional view taken along line C–C′ of FIG. 6.

FIG. 8 is a top view of another arrangement of the top metal plugs andthe metal wall.

FIG. 9 is a top view of yet another embodiment of the inter-layer metalplugs and the metal walls.

DETAILED DESCRIPTION

FIG. 4 is a top view of an embodiment of an integrated circuit device, asemiconductor chip 400, with an edge seal 300 therein sawn from a waferalong a scribe line 401.

As shown in FIG. 5 a, a semiconductor wafer 10 has a dielectric layer 14thereon. The dielectric layer 14 comprises a material with a dielectricconstant less than 3.2, for example a polymer based dielectric or aninorganic material such as a carbon-doped oxide. A plurality of tungstenplugs 12 and a first metal line 16 comprising copper are within thedielectric layer 14. As shown in FIG. 5 e, the first metal line 16 is arectangular ring extending along the periphery 400 a of thesemiconductor chip 400.

A first etching stop layer 18 of silicon nitride, is on the first metalline 16 and the dielectric layer 14. A first inter-metal dielectriclayer 24, having a dielectric constant less than 3.2, is disposed on thefirst etching stop layer 18 such that the first etching stop layer 18 isbetween the first metal line 16 and the first inter-metal dielectriclayer 24. Furthermore, the first etching stop layer 18 acts as an endpoint during etching of first inter-metal dielectric layer 24 to formvia holes for metal plugs and via trenches for metal walls.

A plurality of first metal plugs 20, consisting of copper, in the firstinter-metal dielectric layer 24 are vertically separated from each otherby the first inter-metal dielectric layer 24. First metal walls 22 inthe first inter-metal dielectric layer 24 are laterally adjacent to aperiphery 16 a of the first metal line 16 as shown in FIG. 5 b.Moreover, each of the first metal walls 22 is separated by a distance d2less than 1 micron from the periphery 16 a of the first metal line 16.

First metal plugs 20 and first metal walls 22 comprise a copper layer inthe via holes and the trenches described above.

First metal plugs 20 are disposed in the first inter-metal dielectriclayer 24 preferably in an array as shown in FIGS. 5 a and 5 b. A secondmetal line 26, consisting of copper, overlies the first inter-metaldielectric layer 24. The second metal line 26 is preferably arectangular ring substantially aligned with the first metal line 16 asshown in FIG. 5 d. The first metal plugs 20 and the first metal walls 22connect with the first metal line 16 and a second metal line 26 in thefirst inter-metal dielectric layer 24 as shown in FIG. 5 a.

Alternately, one first metal wall 22 laterally adjacent to the periphery16 a of the first metal line 16 facing the periphery 400 a of thesemiconductor chip, as shown in FIG. 5 c.

A second etching stop layer 28, comprising for example silicon nitride,on the first inter-metal dielectric layer 24 and second metal line 26has a second inter-metal dielectric layer 34 with a dielectric constantless than 3.2 thereon whereby the second etching stop layer 28 isbetween the first metal line 26 and the second inter-metal dielectriclayer 34.

The second etching stop layer 28 acts as an end point during etching ofthe second inter-metal dielectric layer 34 to form via holes for metalplugs and via trenches.

A plurality of second metal plugs 30, consisting of copper, in thesecond inter-metal dielectric layer 34 are vertically separated fromeach other by the second inter-metal dielectric layer 34. Second metalwalls 32 in the second inter-metal dielectric layer 34 are laterallyadjacent to a periphery of the first metal line 26 and substantiallyaligned with the first metal wall 22 in the first inter-metal dielectriclayer 24.

Second metal plugs 30 are disposed in the second inter-metal dielectriclayer 34 in an array. The array of the second metal plugs 30 issubstantially aligned with the array of the first metal plugs 20 underthe second metal plugs 30.

The second metal walls 32 are laterally adjacent to a periphery of thesecond metal line 26 and connect the second metal line 26 and a thirdmetal line 36 in the second inter-metal dielectric layer 34. The secondmetal plugs 30 are also connected to the second metal line 26 and thethird metal line 36. The third metal line 36, consisting of copper,extends along the periphery of the chip and substantially aligned withthe second metal line 26.

A stacked metal structure 80 comprising a plurality of inter-metaldielectric layers, a plurality of metal lines, a plurality of etchingstop layers, a plurality of metal plugs, and a plurality of metal wallsis formed on the second inter-metal dielectric layer 34. Each array ofthe metal plugs in individual dielectric layer is preferably alignedwith others. Furthermore, top metal plugs 60 and top metal walls areformed in the top dielectric layer 102, and a metal line 70 is formed onthe top dielectric layer 102.

Alternately, as shown in FIG. 6 and FIG. 7, the edge seal may comprisean auxiliary edge seal. FIG. 6 is a top view of another embodiment of anintegrated circuit device, a semiconductor chip 600, with an edge sealthereon sawn from a wafer along a scribe line 401 with an edge seal 505comprising a main seal 500 and an auxiliary edge seal 501 disposedsurrounding the main seal 500 to ensure protection of integratedcircuits against moisture and metal contamination.

FIG. 7 is a cross sectional view taken along line C–C′ of FIG. 6 andshows the detailed structures of the edge seal including the main edgeseal 500 and the auxiliary edge seal 501.

A semiconductor wafer 10 has a dielectric layer 14 thereon. Thedielectric layer 14 comprises a material with a dielectric constant lessthan 3.2, for example a polymer based dielectric or an inorganicmaterial such as a carbon-doped oxide. A plurality of tungsten plugs 12and a first metal line 16 comprising copper are within the dielectriclayer 14.

A first etching stop layer 18 for example comprising silicon nitride, isformed on the first metal line 16 and the dielectric layer 14. A firstinter-metal dielectric layer 24, having a dielectric constant less than3.2, is disposed on the first etching stop layer 18 such that the firstetching stop layer 18 is between the first metal line 16 and the firstinter-metal dielectric layer 24. The first etching stop layer 18 acts asan end point during etching of first inter-metal dielectric layer 24 toform via holes for metal plugs and via trenches for metal walls.

A plurality of first metal plugs 20, consisting of copper, in the firstinter-metal dielectric layer 24 are vertically separated from each otherby the first inter-metal dielectric layer 24. First metal walls 22 inthe first inter-metal dielectric layer 24 are laterally adjacent to aperiphery 16 a of the first metal line 16 as shown in FIG. 9. Each ofthe first metal walls 22 is separated by a distance d2 less than 1micron from the periphery 16 a of the first metal line 16.

First metal plugs 20 and first metal wall 22 comprise a copper layer inthe via holes and the trenches described above.

A second etching stop layer 28, comprising for example silicon nitride,is on the first inter-metal dielectric layer 24 and second metal line 26has a second inter-metal dielectric layer 34 with a dielectric constantless than 3.2 thereon whereby the second etching stop layer 28 isbetween the first metal line 26 and the second inter-metal dielectriclayer 34.

The second etching stop layer 28 acts as an end point during etching ofthe second inter-metal dielectric layer 34 to form via holes for metalplugs and via trenches.

A plurality of second metal plugs 30, consisting of copper, in thesecond inter-metal dielectric layer 34 are vertically separated fromeach other by the second inter-metal dielectric layer 34. Second metalwalls 32 in the second inter-metal dielectric layer 34 are laterallyadjacent to a periphery of the first metal line 26.

Second metal plugs 30 are disposed in the second inter-metal dielectriclayer 34 in an array. The array of the second metal plugs 30 is alignedwith that of the first metal plugs 20 under the second metal plugs 30 asshown in FIG. 7.

The second metal walls 32 are laterally adjacent to a periphery of thesecond metal line 26 and connects the second metal line 26 and a thirdmetal line 36 in the second inter-metal dielectric layer 34. The secondmetal plugs 30 are also connected to the second metal line 26 and thethird metal line 36. The third metal line 36, consisting of copper,extends along the periphery of the chip and substantially aligned withthe second metal line 26.

A stacked metal structure 80 comprising a plurality of inter-metaldielectric layers, a plurality of metal line, a plurality of etchingstop layers, a plurality of metal plugs, and a plurality of metal wallsis formed on the second inter-metal dielectric layer 34. Each array ofthe metal plugs in individual dielectric layer is preferably alignedwith others. Furthermore, top metal plugs 60 and top metal walls areformed in the top dielectric layer 102, and a metal line 70 is formed onthe top dielectric layer 102.

Furthermore, the auxiliary edge seal 501 is disposed along the periphery600 a of the semiconductor chip 600 and the main seal 500 as shown inFIGS. 6 and 7. The auxiliary edge seal 501 is between the main seal 500and the periphery 600 a of the semiconductor chip 600. The auxiliaryedge seal 501 comprises tungsten plugs 50 within the dielectric layer14, and a fourth metal line 52 between the first metal line 16 and theperiphery 600 a of the chip. A fifth metal line 26′ is formed in thefirst inter-metal dielectric layer 24 and between the second metal line26 and the periphery 600 a of the chip. A plurality of third metal plugs20′ are formed in the first inter-metal dielectric layer 24 andconnected the forth metal line 52 and the fifth metal line 26′. Also, athird metal wall 22′ is formed in the first inter-metal dielectric layerand laterally adjacent to a periphery of the fourth metal line 52 andconnected the forth metal line 52 and the fifth metal line 26′.

Auxiliary edge seal 501 further comprises metal lines, metal plugs andmetal walls formed in each dielectric layer.

FIG. 8 is a top view of top metal plugs 60 and top metal wall 62.Symbols 70, 16, 26, 36 indicate a projection area of part of the edgeseal 500. Symbol 60 indicates the top metal plugs arranged in an array.Symbol 62 indicates the top metal wall which is disposed adjacent to themetal line 70. On the other hand, symbols 70′, 52, 26′ indicate aprojection area of part of the auxiliary edge seal 501. Symbol 60′indicates the top metal plugs of the auxiliary edge seal 501. Symbol 62′indicates the top metal wall of the auxiliary edge seal 501.

FIG. 9 is a top view of the inter-layer metal plugs and the metal walls.Symbols 70, 16, 26, 36 indicate the projection area of part of the mainseal 500. Symbol 20 indicates the first metal plugs arranged in anarray. Symbol 22 indicates the first metal walls which are disposedadjacent to the first metal line 16 and along the periphery 16 a of thefirst metal line 16. On the other hand, symbols 70′, 52, 26′ indicatethe projection area of part of the auxiliary edge seal 501. Symbol 20′indicates the third metal plugs formed in the inter-layer dielectriclayer of the auxiliary edge seal 501. Symbol 22′ indicates theinter-layer metal wall of the auxiliary edge seal 501.

The auxiliary edge seal 501 outside the main edge seal 500 furtherprotects integrated circuits in the semiconductor ship 600 from moistureand metal contamination while or after the semiconductor chip is sawn.

The first metal wall may be separated by less than one micron from theperiphery of the first metal line and the first metal plugs are arrangedin an array rather than a plurality of metal walls. Therefore,delimitation problem in the conventional structure may be solved.

While the invention has been described by way of example and in terms ofpreferred embodiment, it is to be understood that the invention is notlimited thereto. To the contrary, it is intended to cover variousmodifications and similar arrangements (as would be apparent to thoseskilled in the art). Therefore, the scope of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements.

1. An edge seal for a chip with integrated circuits, comprising: a firstmetal line along a periphery of the chip; a first inter-metal dielectriclayer on the first metal line; a second metal line overlying the firstinter-metal dielectric layer and extending along the periphery of thechip; a plurality of first metal plugs in the first inter-metaldielectric layer connecting the first metal line and the second metalline; and at least one first metal wall in the first inter-metaldielectric layer laterally adjacent to a periphery of the first metalline, in which the first metal wall connects the first metal line andthe second metal line.
 2. An edge seal for a chip with integratedcircuits as claimed in claim 1, further comprising: a second inter-metaldielectric layer on the second metal line.
 3. An edge seal for a chipwith integrated circuits as claimed in claim 2, further comprising: afirst etching stop layer between the first metal line and the firstinter-metal dielectric layer; and a second etching stop layer betweenthe second metal line and the second inter-metal dielectric layer.
 4. Anedge seal for a chip with integrated circuits as claimed in claim 1,wherein the first metal plugs are arranged in an array.
 5. An edge sealfor a chip with integrated circuits as claimed in claim 1, wherein thefirst metal line is substantially aligned with the second metal line. 6.An edge seal for a chip with integrated circuits as claimed in claim 1,wherein the first inter-metal dielectric layer has a dielectric constantless than 3.2.
 7. An edge seal for a chip with integrated circuits asclaimed in claim 1, wherein the first metal plugs are verticallyseparated from each other by the first inter-metal dielectric layer. 8.An edge seal for a chip with integrated circuits as claimed in claim 1,wherein the first metal line and the second metal line comprise copper.9. An edge seal for a chip with integrated circuits as claimed in claim2, further comprising: a third metal line overlying the secondinter-metal dielectric layer and extending along the periphery of thechip; a plurality of second metal plugs in the second inter-metaldielectric layer and connecting the second metal line and the thirdmetal line; and at least one second metal wall in the second inter-metaldielectric layer and laterally adjacent to a periphery of the secondmetal line, in which the second metal wall connects the second metalline and the third metal line.
 10. An edge seal for a chip withintegrated circuits as claimed in claim 9, wherein the second metalplugs are arranged in an array.
 11. An edge seal for a chip withintegrated circuits as claimed in claim 9, wherein the third metal lineis substantially aligned with the second metal line.
 12. An edge sealfor a chip with integrated circuits as claimed in claim 9, wherein thesecond metal plugs are vertically separated from each other by thesecond inter-metal dielectric layer.
 13. An edge seal for a chip withintegrated circuits as claimed in claim 9, wherein the third metal linecomprises copper.
 14. An edge seal for a chip with integrated circuitsas claimed in claim 9, wherein the first metal plugs are aligned withthe second metal plugs.
 15. An edge seal for a chip with integratedcircuits as claimed in claim 1, further comprising: an auxiliary edgeseal along the periphery of the chip dielectrically surrounding thefirst metal line and the second metal line.
 16. An edge seal for a chipwith integrated circuits as claimed in claim 15, wherein the auxiliaryedge seal is between the first metal line and the periphery of the chip.17. An edge seal for a chip with integrated circuits as claimed in claim15, wherein the auxiliary edge seal further comprising: a fourth metalline between the first metal line and the periphery of the chip; a fifthmetal line overlying the first inter-metal dielectric layer and betweenthe second metal line and the periphery of the chip; and a plurality ofthird metal plugs in the first inter-metal dielectric layer andconnecting the fourth metal line and the fifth metal line.
 18. An edgeseal for a chip with integrated circuits as claimed in claim 17, furthercomprising a third metal wall in the first inter-metal dielectric layerlaterally adjacent to a periphery of the fourth metal line.
 19. An edgeseal for a chip with integrated circuits as claimed in claim 1, whereinthe first metal wall is separated apart by a distance less than onemicron from the periphery of the first metal line.
 20. An integratedcircuit device comprising the edge seal according to claim
 1. 21. Anedge seal for a chip with integrated circuits, comprising: a pluralityof inter-metal dielectric layers; a plurality of metal lines, eachformed on the inter-metal dielectric layers and extended along aperiphery of the chip; a plurality of metal plugs in the inter-metaldielectric layers, in which each of the metal plugs connects twoadjacent metal lines; a plurality of metal walls formed in theinter-metal dielectric layers, wherein each of the metal walls is formedadjacent to a periphery of the metal lines and connects two adjacentmetal lines.
 22. An edge seal for a chip with integrated circuits asclaimed in claim 21, wherein the metal plugs are arranged in an array ineach of the inter-metal dielectric layers.
 23. An edge seal for a chipwith integrated circuits as claimed in claim 22, wherein the metal plugsin each of the inter-metal dielectric layers are aligned with those inadjacent inter-metal dielectric layers.
 24. An edge seal for a chip withintegrated circuits as claimed in claim 21, wherein the inter-metaldielectric layers have a dielectric constant of less than 3.2.
 25. Anedge seal for a chip with integrated circuits as claimed in claim 21,wherein the metal lines comprise copper.
 26. An edge seal for a chipwith integrated circuits as claimed in claim 23, wherein the metal linesformed in the adjacent inter-metal dielectric layers are substantiallyaligned with each other.
 27. An edge seal for a chip with integratedcircuits as claimed in claim 21, wherein the metal plugs comprisecopper.
 28. An edge seal for a chip with integrated circuits as claimedin claim 21, wherein each of the metal walls is separated apart by adistance less than one micron from the periphery of at least one of themetal lines.
 29. An integrated circuit device comprising the edge sealaccording to claim
 21. 30. An edge seal for a chip with integratedcircuits, comprising: a plurality of inter-metal dielectric layers; aplurality of metal lines, each formed on the inter-metal dielectriclayers and extended along a periphery of the chip; a plurality of metalplugs in the inter-metal dielectric layers, in which each of the metalplugs connects two adjacent metal lines; and a plurality of metal wallsformed in the inter-metal dielectric layers, wherein the metal wallsformed in adjacent inter-metal dielectric layers are substantiallyaligned with each other.
 31. An edge seal for a chip with integratedcircuits as claimed in claim 30, wherein the metal plugs are arranged inan array in each of the inter-metal dielectric layers.
 32. An edge sealfor a chip with integrated circuits as claimed in claim 31, wherein themetal plugs in each of the inter-metal dielectric layers are alignedwith those in adjacent inter-metal dielectric layers.
 33. An edge sealfor a chip with integrated circuits as claimed in claim 30, wherein theinter-metal dielectric layers have a dielectric constant of less than3.2.
 34. An edge seal for a chip with integrated circuits as claimed inclaim 30, wherein the metal lines comprise copper.
 35. An edge seal fora chip with integrated circuits as claimed in claim 32, wherein themetal lines formed in the adjacent inter-metal dielectric layers aresubstantially aligned with each other.
 36. An edge seal for a chip withintegrated circuits as claimed in claim 30, wherein the metal plugscomprise copper.
 37. An edge seal for a chip with integrated circuits asclaimed in claim 30, wherein each of the metal walls is separated apartby a distance less than one micron from the periphery of at least one ofthe metal lines.
 38. An edge seal for a chip with integrated circuits asclaimed in claim 30, wherein each of the metal walls is formed adjacentto a periphery of the metal lines and connects two adjacent metal lines.39. An integrated circuit device comprising the edge seal according toclaim 30.